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Evaluation of CIE‐lab colour parameters during the clarification of a sugar syrup from Mesquite pods ( Prosopis Pallida L. )
Author(s) -
Larrauri García José A.,
Saura Calixto Fulgencio
Publication year - 2000
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1046/j.1365-2621.2000.00394.x
Subject(s) - lightness , sugar , colorimeter , chemistry , calcium hydroxide , lime , food science , polyphenol , sodium hydroxide , horticulture , botany , mineralogy , biochemistry , materials science , biology , metallurgy , physics , quantum mechanics , optics , antioxidant
Summary There are several commercial sugar syrups obtained from the Mesquite pods, however their dark‐brown colour limits their use in the food industry. In this work we clarified sugar syrups from Mesquite pods by a two‐step procedure: (1) lime‐milk treatment with the addition of different amounts of calcium hydroxide and aluminium sulphate, and (2) ion‐exchange treatment using A‐400 anionic and/or C‐100 cationic resins. Samples were evaluated for colour using the Hunter Lab colorimeter (Hunter Associates Laboratory Inc, Reston, VA, USA) (L*, a*, b*,) and for sensory acceptability during the clarification process. The results showed that with the addition of 7.5% calcium hydroxide and 8.0% aluminium sulphate, followed by treatment with the anionic resin A‐400, a syrup with a high degree of purity (92.3%) and a lighter‐brown colour than other commercial samples could be obtained. The colour values, as measured by the Hunter meter were; a lightness of L* = 6.17 and a yellow colour of 0.74 expressed as a a/b* ratio. A negative correlation was obtained between the total polyphenol content (TP) in the sugar extract and the lightness values (L*); L* = 15.50–0.00511 TP (mg kg –1 ). The A‐400 resin retained the greatest amount of polyphenols (92.9%). CIE‐Lab parameters are proposed as a good means for objective colour comparison with other studies on the clarification of sugar syrups.